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RE: URGENT LUX91 Mono FCUPS power supply schematics

Posted by Thorsten on June 18, 2013 at 11:27:10:
Hi,

If the Amp blows the Mosfet there is a short or excessive current somewhere.

Which Mosfets goes, the one for the negative bias (alone on it's heatsink) or for the HT (two next to each other)?

Normally one should power up the amplifier without output tube, check that voltages are sensible (around 450V HT, Bias starting at around -120V and slowly falling.

The circuits are not complex or unusual, any competent service tech should be able to handle this.